This invention relates to an apparatus which enables to perform a high speed TCP communication on an asymmetric communication line. Namely, it is possible to perform the high speed communication on one way by only setting one apparatus in a case that a large delay section exists in a line among computers.
As shown in FIG. 10, regarding the Internet access service via a satellite communication, a communication satellite 3 is used on a route 6 by which data from a computer 1 at a side of the Internet 9 are sent to a computer 2 at a side of each subscriber. It is supposed that a public network 7 such as a telephone and an ISDN is used for a communication from the computer 2 of each subscriber to the computer 1 in the side of the Internet 9. In FIG. 10, 4 denotes a transmitting equipment for the satellite communication, 5 denotes a receiving equipment for the satellite communication and 8 denotes a router.
The system shown in FIG. 10 is employed because it is difficult for each subscriber to have the transmitting equipment 4 for the satellite communication.
On the other hand, a maximum amount of a window-size, which is used for a flow control in the TCP protocol employed by the Internet, is limited. Therefore, a high speed communication is difficult in a network which uses the satellite communication line 6 having a large transmission delay.
Then, it is required to perform a high speed TCP communication from the Internet 9 to the subscriber in such system shown in FIG. 10.
As a prior art for solving the requirement, a technique, which intends to reduce an effect of the transmission delay by setting gateway apparatuses at both ends of a section with a delay in the communication route between the computers 1,2 and by using an original high speed protocol for a communication between gateway apparatuses, is developed.
However, it is not practical to set the gateway apparatus at each side of the subscribers because very many subscribers are supposed.
An object of the present invention is to provide an apparatus for enabling to perform a high speed TCP communication on an asymmetric communication line without setting a specific equipment at the subscriber""s side in a case that a communication through-put reduces based on the transmission delay such as in the Internet access service via a satellite communication.
In a preferred embodiment, the present invention is directed to an apparatus for high speed communication on an asymmetric line, wherein said apparatus being set at a position on a communication line between a first and second computers which respectively communicates by a communication protocol having a flow control and a transmission delay between said position and said first computer being less than a transmission delay between said position and said second computer, said apparatus comprising; means for generating, instead of said second computer, an ACK packet in response to a data packet sent from said first computer, means for sending and receiving a packet to/from said first and second computers, for transferring to said second computer a data packet which is sent from said first computer and of which data amount is larger than an amount which is notified by said second computer as a maximum by which said second computer can be received, for transferring to said first computer a data packet sent from said second computer, and for doing not transfer to said first computer an ACK packet sent from said second computer, wherein a high speed communication from said first computer to said second computer being performed.
In a further preferred embodiment, the present invention is directed to an apparatus, wherein said communication protocol being the TCP protocol.
In a still further preferred embodiment, the present invention is directed to an apparatus further comprising means for obtaining information regarding a connection between said first and second computers from the SYN packet and the SYN+ACK packet, for recording said obtained information, and for deleting said recorded information after disconnecting said connection.
In a more further preferred embodiment, the present invention is directed to an apparatus further comprising means for storing the FIN packet, wherein said stored FIN packet being transferred after a termination of data transfer.
In another preferred embodiment, the present invention is directed to an apparatus further comprising buffer means for storing said data packet sent from said first computer.
In still another preferred embodiment, the present invention is directed to an apparatus further comprising means for performing a re-transmission process by same procedure as said first computer.
In more another preferred embodiment, the present invention is directed to an apparatus, wherein said first computer being connected with the Internet, a satellite communication line being included in a line from said first computer to said second computer, and a transmission delay of a line from said second computer to said first computer less than a transmission delay of said satellite communication line.
The object of the present application will become more readily apparent from the detailed description given hereafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.